Several types of device have been proposed for protecting vehicle occupants during a crash event. Such devices can be categorized as being either passive devices or active devices.
Passive safety devices deform to absorb energy during a crash event. Passive devices, however, remain in a fixed position during a crash event. Accordingly, there may be a relatively large distance over which the vehicle occupant may accelerate during a crash event before encountering a passive device.
Active safety devices are those that deploy immediately prior to a crash event so that they are positioned relatively close to the vehicle occupants. By reducing the distance between the occupant and the safety device, the occupant has less time to accelerate before encountering the safety device, and therefore is less likely to sustain injury. A typical active safety device incorporates an air bag that inflates prior to a crash event. The air bag is typically a fabric bag that is held in a housing until it is deployed. Air bag devices, however, add complexity and cost to the vehicular subassemblies to which they are added.
It would be advantageous to provide an active safety device that is relatively inexpensive to incorporate into a vehicle.